X-ray mammography systems are widely used for breast imaging. More recently, advanced imaging systems based on tomosynthesis have been developed for use in screening of breast cancer and other lesions. Tomosynthesis systems are three-dimensional (3D) mammography systems that allow high resolution breast imaging based on limited angle tomography at mammographic X-ray dose levels. In contrast to typical two-dimensional (2D) mammography systems, a tomosynthesis system acquires a series of X-ray projection images, each projection image obtained at a different angular displacement as the X-ray source moves along a path, such as a circular arc, over the breast. In contrast to conventional computed tomography (CT), tomosynthesis is typically based on projection images obtained at limited angular displacements of the X-ray source around the breast. Tomosynthesis reduces or eliminates the problems caused by tissue overlap and structure noise present in 2D mammography imaging. Digital breast tomosynthesis also offers the possibility of reduced breast compression, improved diagnostic and screening accuracy, fewer recalls, and 3D lesion localization.
Scattered X-rays generally cause blur and degrade the quality of X-ray images. Anti-scatter grids are typically used in conventional 2D X-ray imaging systems to reduce X-ray scatter by selectively blocking scattered X-rays, such as Compton scattered X-rays, while allowing primary X-rays to reach the X-ray detector. Thus, an anti-scatter grid enhances image quality and tissue contrast by reducing the number of detected X-rays that have been scattered by tissue. While anti-scatter grids have been developed for use in conventional X-ray imaging systems, such as 2D mammography, there is a need for X-ray scatter reducing devices and methods that work with tomosynthesis imaging.